Vestibular Research Laboratory, School of Psychology, the University of Sydney, NSW, Australia.
Acta Otorhinolaryngol Ital. 2009 Aug;29(4):179-86.
This is a review of recently published papers showing that bone-conducted vibration of the head causes linear acceleration stimulation of both inner ears and this linear acceleration is an effective way of selectively activating otolithic afferent neurons. This simple stimulus is used in a new test to evaluate clinically the function of the otoliths of the human inner ear. Single neuron studies in animals have shown that semicircular canal neurons are rarely activated by levels of bone-conducted vibration at 500 Hz which generate vigorous firing in otolithic irregular neurons and which result in a variety of vestibulo-spinal and vestibulo-ocular responses, and the latter is the focus of this review. In humans, 500 Hz bone-conducted vibration, delivered at the midline of the forehead, at the hairline (Fz), causes simultaneous and approximately equal amplitude linear acceleration stimulation at both mastoids and results in ocular-evoked myogenic potentials (oVEMPs) beneath both eyes. The first component of this myogenic potential, at a latency to peak of about 10 ms is a negative potential and is called n10 and, in healthy subjects, is equal in amplitude beneath both eyes, but after unilateral vestibular loss, the n10 potential beneath the eye opposite to the lesioned ear is greatly reduced or totally absent. n10 is a myogenic potential due to a crossed otolith-ocular pathway. In patients with total unilateral superior vestibular neuritis, in whom saccular function is largely intact (as shown by the presence of cervical vestibular evoked myogenic potentials (cVEMPs), but utricular function is probably compromised, there is a reduced n10 response beneath the contralesional eye, strongly indicating that n10 is due to utricular otolithic function.
这是一篇对近期发表的论文的综述，这些论文表明头部骨导振动会引起双耳的线性加速度刺激，而这种线性加速度刺激是选择性激活耳石器传入神经元的有效方法。这种简单的刺激被用于一种新的测试中，以评估人类内耳的耳石器功能。动物的单神经元研究表明，水平方向的骨导振动在 500Hz 时很少激活半规管神经元，而在耳石器不规则神经元中会产生强烈的放电，并导致各种前庭-脊髓和前庭-眼反应，后者是本综述的重点。在人类中，500Hz 的骨导振动，从前额中线、发际线（Fz）处施加，会在两侧乳突同时产生近似相等幅度的线性加速度刺激，从而在双眼下方产生眼源性肌源性电位（oVEMPs）。这个肌源性电位的第一个成分，峰值潜伏期约为 10ms，是一个负电位，称为 n10，在健康受试者中，双眼下方的振幅相等，但在单侧前庭功能丧失后，对侧耳损伤眼下方的 n10 电位大大降低或完全消失。n10 是一种由于交叉耳石-眼通路引起的肌源性电位。在单侧完全性上前庭神经炎患者中，尽管囊状功能基本正常（如颈性前庭诱发肌源性电位（cVEMPs）存在所示），但可能存在椭圆囊功能受损，对侧眼下方的 n10 反应减少，强烈表明 n10 是由于椭圆囊耳石功能。
